Chemical dilution and clearance studies to estimate amniotic fluid volume and amniotic fluid ingestion in normal baboon pregnancies

Amniotic fluid volume (AFV) and amniotic fluid ingestion rate (or fetal swallowing rate, FSR) were estimated by inulin and para-aminohippurate (PAH) dilution in 14 normal baboon pregnancies. Mean (± SE) AFV was significantly lower at 137–140 days of pregnancy (preterm) than at 173–178 days (term) (inulin: 326 ± 22.9 ml vs 483 ± 55.9 ml, P = 0.014; PHA:269 ± 39.4 ml vs 471 ± 39.4 ml, P = 0.002). In proportion to fetal weight, however, mean AFV was similar throughout the third trimester of pregnancy (inulin: 582 ± 40.9 ml/kg; PAH: 541 ± 39.8 ml/kg). Mean FSR was lower in preterm than in term animals when estimated by inulin dilution (587 ± 55.5 ml/day vs 784 ± 55.0 ml/day, P = 0.030) but not when estimated by PAH dilution (753 ± 65.7 ml/day vs 625 ± 50.6 ml/day). In proportion to their weights, however, preterm fetuses swallowed amniotic fluid more rapidly than term fetuses (inulin: 1,216 ± 117.6 ml/kg/day vs 840 ± 67.5 ml/kg/day, P = 0.025; PAH: 1,561 ± 142.9 ml/kg/day vs 682 ± 62.7 ml/kg/day, P < 0.001). Furthermore, our data suggest that the commonly accepted technique for estimating AFV may be based on inaccurate premises, that insulin may be a better marker than PAH to estimate AFV and FSR, and that needle aspiration of amniotic fluid does not appear to be an adequate technique to validate chemical dilution methods. Our data, however, provide estimates which indicate that the baboon is an appropriate animal model in which to seek refinements and validation of our techniques.     

Effect of periphyton on growth performance of grey mullet, Mugil cephalus (Linn.), in inland saline groundwater ponds

The present study attempts to assess the potential of artificial substrates to enhance fish production in inland saline groundwater ponds through periphyton production. Grey mullet, Mugil cephalus, was cultured for 100 days in ponds with substrate (treatment ponds) and without substrate (control ponds). To enhance the surface area, bamboo poles were used as substrate. The periphyton population, pigment concentration and hydrobiological characteristics of pond water were monitored. The studies revealed little difference in most of the water quality parameters observed in the two treatments. However, turbidity (27.0 ± 0.1–35.0 ± 0.1 Nephalo Turbidity Unit (NTU)), chlorophyll ‘a’ (6.6 ± 0.6–7.6 ± 0.6 μg L^?1), plankton population (phytoplankton 8.4 × 10³–9.4 ×10³ numbers L^?1; zooplankton 4.0 × 10³–5.1 × 10³ numbers L^?1) and NH₄–N (2.0 ± 0.2–2.3 ± 0.1 mg L^?1) were high in the treatment with no additional substrate; however, in the treatment with substrate the total Kjeldahl nitrogen (9.8 ± 0.8–10.8 ± 0.7 mg L^?1) and o‐PO₄ (0.1 ± 0.01–0.1 mg L^?1) remained significantly (P < 0.05) higher. Highest periphyton biomass in terms of dry matter (DM) (0.8 ± 0.01–1.4 ±0.01 mg cm^?2), ash free DM (0.4 ± 0.0–0.6 ± 0.01 mg cm^?2), chlorophyll ‘a’ (3.1 ± 0.2–8.1 ± 0.8 μg cm^?2) and pheophytin ‘a’ (1.9 ± 0.4–3.9 ± 0.5 μg cm^?2) was observed at 50 cm depth in ponds provided with additional substrate. Fifteen plankton genera showing periphytic affinity colonized the bamboo substrates. Fish growth (mean fish weight 524.3 ± 8.7 g and SGR 2.5 ± 0.1) was significantly (P < 0.05) higher in ponds provided with additional substrate compared with control ponds (387.2 ± 6.0). Length–weight relationship (LWR) (W = cLⁿ) also showed that the exponential value (‘n’) of length was high in substrate‐supported ponds (n = 2.36) in comparison with controls (n = 1.09). These studies suggest that a periphyton‐supported aquaculture system can be used successfully for the culture of herbivorous brackishwater fish species like M. cephalus in inland saline groundwaters and thus could contribute to the development of sound and sustainable aquaculture technology.     

The production and secretion of cortisol by baboon neonates.

The metabolic clearance rate (MCR), transfer constants (p), production (PR) and secretion (SR) rates of cortisol (F) andrortisone (E) were determined by the continuous infusion of {1,2³H}F and {4-¹⁴C}E into 5 neonates delivered prior to the parturition by cesarean section (164–179 days; term = 184 days) and into 5 newborns delivered spontaneously per vagina at term (166 – 187 days). In spontaneously delivered animals, MCR-E (X ± SE, 34.3 ± 7.0 1/day/kg was greater (P < 0.001) than MCR-F (14.9 ± 1.5 1/day/kg), pF to E (59.7 ± 8.9%) exceeded (P < 0.001) pE to F (17.8 ± 3.0%) and the percentage of F bound to serum proteins other than albumin (57.5 ± 6.2) was greater (P < 0.001) than that of E (27.0 ± 10.3) Although the serum E level (25.6 ± 3.6 μg/100 ml) was similar to that of F (33.5 ± 8.0 μg/100 ml), the PR-E (6.4 ± 1.3 μ/min/kg) was greater (P < 0.001) than PR-F (3.3 ± 0.5 μ/min/kg). Approximately eighty-five percent of the E and 65% of the F produced orginated by secretion.In animals delivered by cesarean section, the serum F concentration (32.4 ± 6.7 μ/100ml), pE to F (13.4 ± 2.8%) pF to E (80.0 ± 12.2%) PR-E (4.5 ± 0.2 μ/min/kg) and SR-E (3.9 ± 0.3 μ/min/kg) were not different from values for spontaneously delivered animals. Serum E levels (35.9 ± 1.6 μ/100 ml) were higher but MCR-F (6.7 ± 0.6 1/day/kg) and MCR-E (18.2 ± 0.41/day/kg) lower in neonates delivered by cesarean section. Serum Cortisol binding capacity (μg F bound/100 ml) was greater (P < 0.025) in neonates delivered by cesarean section (23.6 ± 2.6) than in spontaneously delivered animals (14.4 ± 2.0). As a result of these changes in F and E dynamics, PR-F (1.4 ± 0.3 μ/min/kg) and SR-F (0.9 ± 0.2 μ/min/kg) in neonates delivered by cesarean section were lower (P< 0.01) than corresponding values in spontaneously delivered newborns.It is concluded that the greater F secretion in animals delivered spontaneously than those delivered by cesarean section probably results from increased fetal adrenal 3β-hydroxysteroid dehydrogenase-isomerase activity, which as previously reported, occurs in late gestation in this species.     

Enhanced Weight Loss With Pramlintide/Metreleptin: An Integrated Neurohormonal Approach to Obesity Pharmacotherapy

The neurohormonal control of body weight involves a complex interplay between long‐term adiposity signals (e.g., leptin), and short‐term satiation signals (e.g., amylin). In diet‐induced obese (DIO) rodents, amylin/leptin combination treatment led to marked, synergistic, fat‐specific weight loss. To evaluate the weight‐lowering effect of combined amylin/leptin agonism (with pramlintide/metreleptin) in human obesity, a 24‐week, randomized, double‐blind, active‐drug‐controlled, proof‐of‐concept study was conducted in obese or overweight subjects (N = 177; 63% female; 39 ± 8 years; BMI 32.0 ± 2.1 kg/m²; 93.3 ± 13.2 kg; mean ± s.d.). After a 4‐week lead‐in period with pramlintide (180 µg b.i.d. for 2 weeks, 360 µg b.i.d. thereafter) and diet (40% calorie deficit), subjects achieving 2–8% weight loss were randomized 1:2:2 to 20 weeks of treatment with metreleptin (5 mg b.i.d.), pramlintide (360 µg b.i.d.), or pramlintide/metreleptin (360 µg/5 mg b.i.d.). Combination treatment with pramlintide/metreleptin led to significantly greater weight loss from enrollment to week 20 (?12.7 ± 0.9%; least squares mean ± s.e.) than treatment with pramlintide (?8.4 ± 0.9%; P < 0.001) or metreleptin (?8.2 ± 1.3%; P < 0.01) alone (evaluable, N = 93). The greater reduction in body weight was significant as early as week 4, and weight loss continued throughout the study, without evidence of a plateau. The most common adverse events with pramlintide/metreleptin were injection site events and nausea, which were mostly mild to moderate and decreased over time. These results support further development of pramlintide/metreleptin as a novel, integrated neurohormonal approach to obesity pharmacotherapy.     

Electrocardiographic evidence for cocaine cardiotoxicity in cat

Recent case studies suggest that cocaine overdose may produce life-threatening cardiac arrhythmias. We therefore investigated its effects on the electrocardiogram (leads II and V1) and arterial blood pressure in cats anesthetized with pentobarbital. Cocaine was administered by intravenous infusion over a 2-min interval at 1 mg/kg in 10 cats. In 5 out of 10 cats an additional infusion of 3 mg/kg cocaine was also administered after hemodynamic and electrocardiographic parameters had returned to control values (i.e., within 10 min). During and following infusion of 1 mg/kg cocaine, no significant change in heart rate or systolic or diastolic blood pressure were found, however the QRS duration increased by 38% (from 46 +/- 5 to 64 +/- 12 ms) (p less than 0.01). Evidence for bundle branch block and (or) premature ventricular beats was observed in 9 out of 10 cats after 1 mg/kg cocaine. Infusion of a further 3 mg/kg cocaine in five cats significantly lowered diastolic blood pressure (from 98 +/- 18 to 64 +/- 28 mmHg; 1 mmHg = 133.3 Pa) (p less than 0.01), and further prolonged QRS to 79 +/- 14 ms, a 75% increase from the mean control value (p less than 0.01). In addition, 1st and 2nd degree atrioventricular block, ventricular extrasystoles, and ectopic rhythms (AV junctional or idioventricular) were observed in four out of five cats given 3 mg/kg cocaine. Mean plasma concentrations of cocaine were 1.37 +/- 0.39 micrograms/mL (4.28 +/- 1.22 microM) (n = 5) at the end of a 1 mg/kg infusion and 2.93 +/- 0.43 micrograms/mL (9.16 +/- 1.34 microM) after a 3 mg/kg infusion (n = 3).(ABSTRACT TRUNCATED AT 250 WORDS)     

Genetic polymorphisms of the bovine Fatty acid binding protein 4 gene are significantly associated with marbling and carcass weight in Hanwoo (Korean Cattle)

The objective of this study was to investigate an association between polymorphisms in the FABP4 gene and phenotypic variation for marbling and carcass weight (CWT) in a population of Hanwoo steers. We re‐sequenced 4.3 kb of the FABP4 gene region in 24 Hanwoo bulls and identified 16 SNPs and 1 microsatellite polymorphism. Of these 16 SNPs, three SNPs [g.2774G>C (intron I), g.3473A>T (intron II) and g.3631G>A (exon III, creating a p.Met >Val amino acid substitution)] were genotyped in 583 steers to assess their association with carcass traits. The g.3473A allele showed a significant increasing effect on CWT (P = 0.01) and the g.3631G allele was associated with higher marbling score (P = 0.006). One haplotype of these three SNPs (CAG) was significantly associated with CWT (P = 0.02) and marbling score (P = 0.05) and could potentially be of value for marker assisted selection in Hanwoo cattle. The CAG haplotype effect for CWT was larger (11.14 ± 5.03 kg) than the largest single locus effect of g.3473A>T (5.01 ± 2.2 kg).     

家燕和金腰燕的卵胚胎心率比较

胚胎心率是衡量胚胎新陈代谢速率的重要指标。鸟类的胚胎心率随新陈代谢的增加而呈上升趋势。对早成性鸟类的种间比较发现,胚胎心率平均值随卵重量的增大而减小,卵体积小的种类具有相对较高的胚胎心率。国内有关野生鸟类胚胎心率的研究较少。2014年5~8月,在黑龙江扎龙国家级自然保护区,利用红外胚胎心率测量仪对两种近缘鸟类家燕(Hirundo rustica,n=14)和金腰燕(Cecropis daurica,n=14)的卵胚胎心率及其变化进行了测量与比较。两种燕均在孵卵的第2天开始出现胚胎心率,并随胚龄增加心率呈上升趋势,但在第8天及第11~14天家燕的胚胎心率显著低于金腰燕(第8天:z=﹣2.602,P=0.009;第11天:z=﹣2.497,P=0.013;第12天:z=﹣2.354,P=0.019;第13天:z=3.424,P=0.001;第14天:z=﹣3.380,P=0.001)。家燕卵胚胎日均增长心率(19.0±3.1)次/min,金腰燕卵胚胎日均增长心率(16.1±3.4)次/min,二者差异不显著(z=﹣1.792,P=0.073)。两种燕的胚胎心率与卵容量和卵重均不存在显著相关性[家燕:卵容量(1.73±0.09)cm3,r=0.192,P=0.511;卵重(1.74±0.09)g,r=0.128,P=0.663。金腰燕:卵容量(1.74±0.08)cm3,r=0.040,P=0.891;卵重(1.51±0.09)g,r=0.054,P=0.855]。这可能表明,卵大小和卵重量对家燕与金腰燕的胚胎心率均影响不明显。     

Creatine feeding does not enhance intramyocellular glycogen concentration during carbohydrate loading: an in vivo study by31P-and13C-MRS

The main aim of this study was to examine the hypothesis that creatine (Cr) feeding enhances myocellular glycogen storage in humans undergoing carbohydrate loading. Twenty trained male subjects were randomly assigned to have their diets supplemented daily with 252 g of glucose polymer (GP) and either 21 g of Cr (CRGP, n=10) or placebo (PL-GP, n=10) for 5 days. Changes in resting myocellular glycogen and phosphocreatine (PCr) were determined with Magnetic Resonance Spectroscopy (¹³C- and³¹P-MRS, respectively). After CR-GP, the levels of intramyocellular glycogen increased from 147±13 (standard error) mmol·(kg wet weight)^?1) to 182±17 mmol·(kg wet weight)^?1, while it increased from 134±17 mmol·(kg wet weight)^? to 182±17 mmol·(kg wet weight)^?1 after PL-GP; the increments in intramyocellular glycogen concentrations were not statistically different. The increment in the PCr/ATP ratio after CR-GP (+0.20±0.12) was significantly different compared to PL-GP (?0.34±0.16) (p<0.05). The present results do not support the hypothesis that Cr loading increases muscle glycogen storage.     

Differences in productive robustness in rabbits selected for reproductive longevity or litter size

The aim of this work was to evaluate the ability of a line selected for reproductive longevity (LP) to confront productive challenges compared to a line selected during 31 generations for litter size at weaning (V). A total of 133 reproductive rabbit does were used (72 and 61 from LP and V lines, respectively). Within each line, three groups with different levels of productive effort were planned: PP9, inseminated at day 4 after the first partum and with nine kits during the second partum, and inseminated after first weaning (30 days) and with nine (PW9) or five kits (PW5) during the second partum. The reproductive performance, body condition (perirrenal fat thickness (PFT)) and lipolytic response were controlled. LP does showed greater mean live weight (LW; +128 g; P < 0.05), PFT (+0.47 mm; P < 0.05) and estimated body energy (EBE; +0.29 MJ/kg; P < 0.01) than V does at second partum. However, LP does that mated at first post partum did not significantly differ in EBE relative to V does at second partum. During the first week of lactation, dry matter (DM) intake was similar for both lines (94 and 95 g DM/kg LW0.75 day for V and LP does, respectively). There was a significant difference in milk yield between both lines during the first week when litter size was nine (60 v. 54 g of milk/kg LW0.75 day for LP and V does, respectively; P < 0.01), but no difference when litter size was five. Consequently, when litter size was nine, LP does showed a lower recovery of PFT (0.6 mm less; P < 0.05) than V does during the first 10 days of lactation. However, when litter size was five, LP does showed a higher LW (+210 g; P < 0.05) than V does at 10 days of lactation and a similar recovery of PFT. During the last 3 weeks of the lactation, LP does showed a higher feed intake (+6 g DM/kg LW0.75 day; P < 0.05) and milk yield (+27 g/day; P < 0.001) than V does when litter size was nine, resulting in no significant differences in LW at 30 days of lactation. However, when litter size was five, both lines showed similar feed intake and milk yield, maintaining their differences in LW at 30 days of lactation (+206 g for LP does; P < 0.05). These results show that the rabbit line selected for reproductive longevity is more robust with respect to coping with productive challenges, than a line selected for reproductive intensity.     

Elevated levels of urinary 17-ketosteroids in central Indian children residing near sewage treatment plant and solid waste disposal plant: A preliminary study

Urinary excretion of 17-ketosteroid (17-KS) was assessed in male pre-pubertal subjects aged (8–11 years; n = 90). Children living near sewage treatment plant and solid waste disposal plant (Group P) showed significantly higher levels of urinary 17-KS (Group P: 3.27 ± 1.63 µg/mL/CRE; p < 0.01) than children living in cleaner area (0.50 ± 0.53 µg/mL/CRE; Group C). Occurrence of urinary dibutyl phthalate in representative subjects of Group P (odds ratio: 9; p < 0.05; 95% of Confidence interval (CI) 1.93–72.99) was higher compared to Group C. Urinary concentrations of Cd (0.85 µg/g CRE ± 0.11), Mn (24.25 µg/g CRE ± 6.11) and Pb (12.39 µg/g CRE ± 2.86) in Group P were significantly (p < 0.01) higher than those found in Group C (Cd (0.28 µg/g CRE ± 0.03), Mn (13.33 µg/g CRE ± 3.20) and Pb (5.67 µg/g CRE ± 0.53)). Analyses of ambient air samples (PM₁₀) in polluted area revealed major occurrence of phthalates, whereas derivatives of trifluoromethyl, dione, etc. were identified in PM_2.5 fraction. Metal (Cd, Co, Mn and Pb) concentrations in ambient air (24 h, PM₁₀) were higher in polluted area compared to cleaner area. We conclude that elevated levels of urinary 17-KS in Group P could be attributed to higher exposure of these subjects to Endocrine disrupting chemicals (EDCs) compared to Group C.     

Differential Metabolic Effects of Energy Restriction in Dogs Using Diets Varying in Fat and Fiber Content

The role of dietary fat and fiber in energy restriction for the management of obesity was examined. Twelve male castrated dogs were energy restricted for 7 weeks by feeding 60% of their calculated maintenance energy requirements (MER = 1500 kcal/m²/d) for ideal body weight. Six dogs were restricted on a high-fat (35.4 kcal% from fat), low-fiber (2.9% dry matter basis [DMB]) diet while the other six dogs were restricted on a low-fat (24.5 kcal% from fat), high-fiber (27% DMB) diet. Compared with the high-fat, low-fiber diet, energy restriction on the low-fat, high-fiber diet resulted in significantly greater decreases in body fat (1472 ± 166 vs. 853 ± 176 g; p < 0.05) and total serum cholesterol concentrations (108.7 ± 11.3 vs. 51.5 ± 13.9 mg/dL; p< 0.005). Reductions in body weight (2.86 ± 0.3 vs. 2.14 ± 0.3 kg; p< 0.09), and mean arterial blood pressure (17.4 ± 6.1 vs. 6.7 ± 2.9 mmHg; p < 0.12) were also greater on the low-fat diet; however, these diet effects did not reach statistical significance. These data suggest that the fat and fiber content of the diet during energy restriction are important factors in the management of obesity.     

Alpha melanocyte stimulating hormone inhibits prolactin secretion in fetal and infant lambs

The intravenous administration of αMSH (25 μg/kg) to 11 lambs (3 to 29 days of age) suppressed plasma PRL by 15 minutes. The mean basal concentration was 15.3 ± 2.9 ng/ml and the mean nadir was 4.9 ± 0.8 ng/ml (p<0.01). In chronically catheterized fetuses (128–140 days), intravenous administration of αMSH (25 μg/kg) decreased basal PRL levels (89.6 ± 12.4 ng/ml) significantly at 15–30 minutes to levels of 74.3 ± 11.4 ng/ml (p<.01). The degree of suppression of basal PRL levels was less in fetusus (76.9 ± 4.1%) than that induced in the neonates (40.5 ± 7.1%). In younger fetuses <120 days in whom basal PRL levels are low (3.0 ± 2.1 ng/ml), administration of αMSH was without effect. Plasma GH concentrations were not altered by administration of αMSH. The suppression of PRL secretion by αMSH administration could result from increased release of hypothalamic dopamine or be a direct effect on secretion of prolactin by the pituitary.     

Effect of decreasing dietary protein level and replacing starch with soluble fibre on digestive physiology and performance of growing rabbits

At weaning (33 days of age), 246 hybrid rabbits (782 ± 53 g live weight) were divided into six experimental groups and fed ad libitum six iso-ADF diets formulated according to a bifactorial arrangement with two protein levels (152 and 162 g/kg) and three soluble fibre-to-starch ratios (0.2, 0.6 and 1.5), the latter obtained by replacing starch (from 209 to 91 g/kg) with soluble fibre (from 48 to 136 g/kg). The trial lasted for 42 days until slaughter. The rabbits that were fed the diet with the highest protein level and the lowest soluble fibre-to-starch ratio showed the highest mortality rate (17.1% v. 1.7% on average; P < 0.001) and sanitary risk (mortality + morbidity: 20.0% v. 8.1%; P = 0.04) compared with the rabbits fed the other diets. With increasing dietary crude protein level, the digestibility of dry matter (DM; 0.615 to 0.626) and gross energy (0.620 to 0.630) as well as aNDF (without sodium sulphite; 0.298 to 0.323) and hemicelluloses (0.417 to 0.461) significantly (0.001 < P < 0.10) improved. Moreover, total volatile fatty acids (VFAs) in the caecal content increased (59.0 to 68.4 mmol/l; P = 0.01) and ileum crypt depth tended to reduce (P = 0.07). Neither growth performance nor slaughter results were affected by the protein level. When increasing soluble fibre-to-starch ratio, the digestibility of DM and gross energy did not change, whereas the digestibility of aNDF (0.264 to 0.352), ADF (0.167 to 0.267) and hemicelluloses (0.400 to 0.470) linearly increased (P < 0.001). At caecum, N-ammonia tended to decrease linearly (P = 0.08), total VFA concentration (56.0 to 67.3 mmol/l) and acetate proportion (80.4 to 83.3 mmol/100 mmol VFA) linearly increased (P < 0.01), whereas butyrate and valerate proportions decreased (0.01 < P < 0.05). Growth performance was similar among groups, whereas at slaughter the proportion of the gastrointestinal tract linearly increased (177 to 184 g/kg; P < 0.01) without effect on dressing percentage, however. As soluble fibre-to-starch ratio increased, meat pH linearly decreased and lightness (L*), redness (a*) and yellowness (b*) colour indexes increased (0.01 < P < 0.05).     

Day-Night Differences in the Kinetics and Dynamics of Insulin: Diabetic Versus Normal Yucatan Minipigs

Time-dependent variations in the pharmacokinetics and pharmacodynamics of insulin were studied at two times, 10:30 and 20:30 during the same day in normal and streptozotocin (STZ)-induced diabetic minipigs housed in L(06:00):D(18:00) using the intravenous insulin tolerance test. Following intravenous insulin (0.1 IU/kg) administration in normal minipigs, the time for the glucose level to reach nadir (t_nadir) was significantly longer in the evening than the morning [(a.m.: 30.4 (± 2.4) VS. P.M.: 38.5 (± 3.3) min] (p < 0.01), although maximum reduction of glucose level (nadir) in the morning and evening was not significantly different [a.m.: (-70 (± 2) VS. P.M.: -65 (± 5) %]. The rate of glucose decline (K_in) was significantly decreased in the evening [a.m.: 5.33 (± 0.71) VS. P.M.: 4.44 (± 0.54) %dBG/min] (p < 0.01), and the integrated glucose-lowering response (ABCB) was significantly higher in the evening than the morning [a.m.: 3.18 (± 0.38) VS. P.M.: 4.52 (± 0.30) (g/dl) * min] (p < 0.01). The area under the plasma insulin concentration curve was increased significantly in the evening [a.m.: 2.26 (± 0.174) VS. P.M.: 2.74 (± 0.18) (mU/ml) * min], while the morning plasma insulin half-life did not differ significantly from that in the evening [a.m.: 4.79 (± 0.36) VS. P.M.: 5.47 (± 0.47) min]. After induction of diabetes by intravenous STZ injections, minipigs became diabetic, baseline blood glucose was observed to increase from the range of 45–55 to 200–250 mg/dl while plasma insulin levels decreased from 7–12 to 3–5 uU/ml. In the STZ-induced diabetic minipigs, a higher dose (0.2 IU/kg) was used in the intravenous insulin tolerance test in an attempt to normalize the high glucose levels. Following intravenous     

The utilization of placental substrates for cortisol synthesis by the baboon fetus near term

We have determined the proportion of the invivo cortisol (F) secretion rate (SRF) derived from circulating pregnenolone (P5) and progesterone (P4) in 9 baboon (Papiopapio) neonates, 5 (4 ♂, 1 ♀) delivered prior to the onset of labor by cesarean section (CS, 164–179 days) and 4 (2 ♂ , 2 ♀) delivered spontaneously at term (SD, 164–179 days; term = 184 days). The metabolic clearance rate (MCR; 1/d/kg) and production rates (PR; mg/d/kg) of P4 and P5 and transfer constants (p) for the reactions P5 → P4₁₄ P5 → F, and P4 → F, were determined by continuous infusion of [1,2-³H] P5 and [4-¹⁴C] P4.In CS animals the MCR-P5 (41.4 ± 5.6; X ± SE) was lower than the MCR-P4 (74.0 ± 8.5; P < 0.001). However, the pP5 → F (1.0% ± 0.3%) and pP4 → F (0.9% ± 0.3%) were similar although lower (P < 0.001) than pP5 → P4 (9.0% ±1.4%). The PR-P4 (7.0 ± 0.8) was 4–5 times greater than the PR-P5 (P < 0.01). In SD newborns, only the pP5 → F (3.4% ± 0.9%) and the PR-P4 (0.5 ± 0.2) were different (P < 0.01) from values in CS neonates. These results indicate that although the baboon fetus has the capacity to convert P5 to P4, the abundant quantities of P4 measured in fetal serum (95 ± 12 ng/ml) near term are primarily placental in origin. Moreover, the apparently low (< 5%) transfer constants for the conversion of P5 or P4 to F suggests minimal utilization of these circulating precursors for F synthesis. Indeed, the calculated proportion of the SR-F derived from circulating P4 was 5.3% ± 2.0% in CS neonates and only 0.3% ± 0.1% in SD newborns. In these animals, values for the utilization of circulating P5 were 1.4% ± 0.4% and 1.6% ± 0.4%, respectively.We conclude that endogenous adrenal substrates and not placental substrates are the primary precursors utilized for fetal adrenal F production in late baboon gestation.     

Effects of substance P on renin release and renal function in anesthetized dogs.

Substance P (SP), a naturally occuring undecapeptide with hypotensive, vasodilatory and smooth muscle stimulating properties, was infused intravenously or intrarenally into anesthetized dogs. Infusions of SP intravenously suppressed renin secretion rate (RSR) from 204±45 to 52±18 ng/min (p < 0.02) at an infusion rate of 0.5 ng/kg/min, and to 50±22 ng/min (p < 0.05) at 5 ng/kg/min. When the concentration of SP was further increased to 50 ng/kg/min, RSR increased to a level above the control value (728±81, p < 0.01). Intrarenal infusion of SP produced similar changes in renin release. At infusion rates of 0.5 ng/kg/min and 5 ng/kg/min, RSR was suppressed from 145±18 to 56±18 ng/min (p < 0.05) and to 26±8 ng/min (p < 0.01) respectively. At 50 ng/kg/min, RSR increased to 251±59 (p > 0.1). Both intravenous and intrarenal administration of the peptide significantly lowered arterial blood pressure at the highest two doses. Intrarenal infusion of SP resulted in a significant dose-related increase in urine volume, sodium and potassium excretion, and renal blood flow. In contrast, intravenous infusions did not alter these parameters. Thus SP suppresses renin release in the presence and in the absence of diuresis, natriuresis, and vasodilation.     

Chronic Application of MTII in a Rat Model of Obesity Results in Sustained Weight Loss

Objective: To examine the effects of a cafeteria diet and a chronic treatment with melanocortin agonist (MTII) on mature weight-stable female rats. Research Methods and Procedures: Ex-breeder Chbb:Thom rats (350 to 400 g) were divided into two groups: highly palatable food (HPF) and normal rat chow (RC). Both groups had ab libitum access to rat chow. The HPF group had access to chocolate bars, cookies, cheese, and nuts (∼20 g/d). After 21 days, the rats in each group were then divided into control and treated groups. Mini-pumps delivering saline or MTII (1 mg/kg per day) for minimally 28 days were implanted. Oxygen consumption was measured for 17 days in a second group of rats implanted with mini-pumps containing MTII (1 mg/kg per day) or saline. Results: HPF rats ate less (<50%) rat chow than RC rats. After 20 days, the HPF group had reached a plateau and weighed significantly more (p < 0.005) than the RC group (411.7 ± 9.3 g; n = 17 vs. 365.1 ± 9.4 g; n = 16). HPF rats and RC rats receiving MTII reduced their pellet intake and body weight in the initial 2 weeks of treatment (day 14, RC-saline: −1.6 ± 1.8 g; RC-MTII, −22.5 ± 3.7 g; HPF-saline, −7.1 ± 1.7 g; HPF-MTII, −30.7 ± 4.8 g). Subsequently, pellet intake returned to pre-implantation values, although body weights remained reduced in both HPF and RC groups. Oxygen consumption was increased in rats treated with MTII. Discussion: This suggests that MTII initially reduced body weight by limiting food intake; however, maintenance of weight is most likely due to increased energy expenditure under conditions of normal and highly palatable diets in mature animals.     

Influence of various amounts of fumaric acid on performance and parameters of the acid–base balance of growing bulls fed with grass or maize silage

The aim of the present study was to determine the effects of the potential methane reducer fumaric acid on the fattening performance and acid–base balance of growing bulls fed two different silage types as roughage (maize and grass silage). A total of 62 fattening bulls (German Holstein breed, initial body weight: 266 ± 42 kg), randomly assigned to eight feeding groups, received four levels of fumaric acid (0, 100, 200 or 300 g/d) at each silage type. The daily feed and water intake and the live weight were measured over the whole testing period of 280 days. In blood samples, blood cells and blood gases as a parameter of acid–base status were analysed. Feed and faeces were collected to determine the apparent nutrient digestibility. Five animals from each group fed maize or grass silage, supplemented with 0 g or 300 g fumaric acid, were slaughtered at 580 kg body weight. After slaughter, rumen fluid pH was measured and dressing percentage was calculated. Neither the total feed intake (8.81 ± 0.07 kg/d) nor the daily weight gain (1277±24 g/d) was influenced significantly by treatments. Fumaric acid supplementation did not influence the erythrocyte count or the blood gas concentration. The silage type significantly influenced the apparent digestibility of the whole diet. The dressing percentage was slightly higher (p < 0.1) after fumaric acid supplementation. No signs of an incompatibility to fumaric acid on the animals were observed over the whole experimental period. However, it seems to be necessary to conduct more long-term studies with different silage types and addition of organic acids combined with direct measurements of methane.     

Effects of a nonperssor analogue of vasopressin on plasma renin activity and salt and water excretion in water-loaded,anesthetized dogs

The object of this study was to determine the importance of vasoconstrictor activity in the suppression of renin secretion by vasopressin. Arginine vasopressin (AVP) (0.05 and 0.1 ng/kg/min) and a nonpressor analogue of vasopressin, 1-deamino-[4-threonine, 8-D-arginine]-vasopressin (dTDAVP) (0.01 and 0.05 ng/kg/min), were infused intravenously in anesthetized hypophysectomized dogs. Neither dTDAVP nor AVP influenced arterial pressure or heart rate but both suppressed plasma renin activity. Infusion of dTDAVP at 0.01 and 0.05 ng/kg/min suppressed plasma renin activity to 86±4% (p<0.05) and 63±6% (p<0.01) of the control values respectively. Infusion of AVP at 0.05 and 0.1 ng/kg/min suppressed plasma renin activity to 60±8% (p<0.01) and 59±12% (p<0.05) of the central values respectively. dTDAVP and AVP both produced significant increases in sodium excretion. These data demonstrate that vasoconstrictor activity is not required for the effects of vasopressin on renin secretion and sodium excretion.